Sonic energy apparatus



P 1958 A. MURDOCH, JR I 2,854,012

SONIC ENERGY APPARATUS Filed Jan. 15, 1954 2 Sheets-Sheet 1 INVENTOR. ALEXANDER MURDOCH JR 7 6/5 ATTOE/VEYS Sept. 30, 1958 A. MURDOCH, JR

SONIC ENERGY APPARATUS Filed Jan. 15, 1954 2 Sheets-Sheet 2 FIG. 2.

IN VEN TOR. ALEXAN DER MURDOCF-LJR fi/S 47702/1/516' United States Patent SONIC ENERGY APPARATUS Alexander Murdoch, In, Port Washington, N. Y., as-

signor to Telephonics Corporation, Huntington, N. Y., a corporation of New York Application' January 15, 1954, Serial No. 404,225

Claims. Cl. 134-116) invention relates to apparatus for generating and utrllzrng compressional wave energy in the sonic and ultra-sonic ranges.

Compressional wave energy in the sonic and ultrasonic ranges has, in the past, been found useful in numerous processes such as in forming emulsions, mixing ordinarily immiscible compounds, homogenizing liquids, destroying bacteria, degassing liquids, producing sintered metal from a plurality of different pulverulent materials and other similar processes well known in this art. However, diificulties have been encountered in providing compressional wave energy at high intensities to carry out these processes.

In attempting to overcome these difficulties, magnetostrictive vibrators have been employed which although proving satisfactory inmany respects, exhibit certain disadvantages. Foremost among these are the overheating of the magnetostrictive element at high power levels and the difliculty of coupling the vibrations into the container wherein the process is to be carried out. Obviously, it is desirable to transfer as great a portion of the energy from the magnetostrictive transducer to the container as possible, but in numerous instances, it is not feasible to directly introduce the vibrating element into the container. Thus, if a corrosive liquid is placed therein, the vibrating elements may be damaged. Furthermore, fluid leakage at the point of introduction of the vibrator into the container is troublesome.

Further difliculties have also been experienced in cleaning small articles when immersed in a cleaning fluid and subjected to compressional wave energy. This is especially true if the article is provided with normally relatively movable surfaces which will, however, remain stationary in the container. Accordingly, such surfaces will not be cleaned at their points of contact.

The present invention provides methods and apparatus for overcoming the above-enumerated deficiencies of magnetostrictive vibrating apparatus and cleaning methods. In describing the invention, confusion will be avoided if the term sonic energy is understood to refer to compressional waves at frequencies extending to ap-' proximately 50 kilocycles.

Apparatus in accordance with the present invention comprises a plurality of magnetostrictive vibrators transferring energy through coupling means to a container. In a preferred embodiment of the invention, supporting means are provided within the container to aid in' the rapid and thorough cleansing of small articles. A further feature of the invention comprises means for removing the cleaning fluid and dirt from the container during the cleansing process.

The invention further contemplates a novel cleaning method for articles with relatively movable surfaces. Thus, by suitably mounting and positioning such articles in the cleaning fluid, the surfaces will be kept in constant motion and completely cleansed.

Furthermore, the methods of the present invention include pickling and etching of articles with greater efii- 2,354,012 Patented Sept. 30, 1958 ciency and improved results. Also, an improved method for removing burrs and other rninute particles from various objects is provided by the action of sonic wave energy through a liquid medium.

Further advantages of the present invention will be more readily understood when the following description is read in connection with the accompanying drawings in which:

Figure l is a plan view of sonic wave energy apparatus constructed in accordance with the present invention;

Figure 2 is a view in section taken on the line 2-2 of Figure 1 looking in the direction of the arrows;

Figure 3 is a view in elevation of modified sonic wave energy apparatus constructed in accordance with the invention; and

Figure 4 is a View in section taken on the line 44' of Figure 3 looking in the direction of the arrows.

Referring to the drawings in greater detail with particular reference to Figures 1 and 2, a container 10, preferably cylindrical in form and illustrated with a fiat bottom, is constructed from corrosion-resistant material such as stainless steel and has an inlet tube 11 joined to a supply line 12, carrying a valve 12a for controlling the flow of any desired liquid 13. Preferably, the inlet tube is terminated by an elbow 11a adapted to discharge the incoming liquid 13 circumferentially with respect to the container 10 to provide circulation therein. It should be understood that if desired for better drainage, the bottom of the container 10 may be inclined toward the outlet 14.

Found in the center of the container 10 is an outlet tube 14 joined to a discharge line 15 leading to a valve 16. It will be apparent that the swirling action of the incoming liquid will tend to concentrate foreign matter therein at the center of the container 10, such matter being removed by selective operation of the valve 16.

It may be desirable, in certain instances, to provide a circular supporting rack 17 resting on the floor of the container 10. The rack 17 may consist of wire that is shaped to provide upwardly extending tapering fingers 17a carrying pins 17b for supporting articles such as, for example, ball bearings 18 as illustrated. Tapering the fingers 17a permits the rack 17 to accommodate a great range of differently shaped and sized articles while the pins 17b, attached thereto in any manner such as by I soldering, prevents articles from resting on the floor of the container 10 and supports certain objects in a lateral position.

The ball bearings 18 are formed from an outer race 19, balls 20, and an inner race 21. When placed upon the fingers 17a, they will besupported bythe pins 17b if the diameter of the inner race 21 is great enough.

It is obvious that other forms of racks and articles may .be provided within the container10, the above description and showing being exemplary'only. I

In order to subject articles within the container 10 to high intensity sonic wave'energy, a plurality of magnetostrictive vibrators 25, four being shown in this particular embodiment of the invention, are coupled to the floor of the container 10 in a manner to be described hereinafter. Each of the magnetostrictive vibrators 25 consists of a one-half wavelength laminated stack 26 formed from nickel plates or other plates of magnetostrictive material. The stack 26 is fastened in, a conventional mannersuch as welding, soldering, or gluing into a shallow recess 27 in atruncated conical member 28 attached to the bottom of the container 10. The members 28 maybe formed, for example, from aluminum and function to efiiciently couple sonic energy from the stacks 26 to the.

container 10 by matching the acoustical impedance of Conventional methods may be employed to join the members 28 to the container 10, and it has been found in one exemplary embodiment that a plating of aluminum on the bottom ofthe container will permit the member 28 when formedfrom aluminum to be readily cemented thereto. In certain instances, a hollowed out portion 28a may be provided in the members 28, as shown in Fig. 3, a complete description of the sonic energy coupling member 28 being setforth in my copending application Serial No. 387,757, filed October 22, 1953, now abandoned.

In order to energize the magnetostrictive vibrators 25, coils 29,-adapted to be energized from an A.-C. power supply through conductors 29a, are centrally positioned concentric with each of the stacks 26 and preferably supported on aplate 30 byscrews 31. The plate 30 rests on pins 32 inserted in upright spacers 33, in turn joined to locating plates 34 and 35 at the upper and lower extremities thereof, respectively, by bolts 36.

Disposed between the plates 34 and 35 and fitted into cylindrical recesses 37 and 38 therein is a magnet 39 for furnishing a constant polarizing .magnetic field to the magnetostrictive stacks 26. The magnetic flux path includes the magnet 39, the plates 34 and 35 preferably formed from soft steel, and the magnetostrictive stacks 26.

An inverted box 40-is provided to support the magnet and vibrator assemblies by having portions thereof inserted between the upright spacers 33 and the plate 35. A plurality of supports 41, extending from the container 10, are joined to the box; 40 in order to position the vibrators 25 in a desired relation to the magnet and coil assemblies.

It is to be understood that the unitary bar magnet illustrated is exemplary only and other means of furnishing a polarizing magnetic flux may be employed. For example, an alternative arrangement for energizing the magnetostrictive vibrators is schematically illustrated in Figures 3 and 4 in which elements similar to those found in Figures 1 and 2 are designated by the same reference numerals. In order to provide a polarizing field for the magnetostrictive vibrators 25, four bar magnets are positioned by conventional supporting means (not shown) to extend between the upper portions of the stacks 26 and cooperate with four bar magnets 51 extending between the lower portions of the stacks 26. The polarities of the magnets 50 and 51 are arranged, as shown in Figures 3 and 4, to provide magnetic flux in each of the stacks 26. Shields 52 and 53 formed, for example, from copper or aluminum, are provided below the magnets 50 and above the magnets 51, respectively, in order to concentrate the A.-C. fiux therebetween to improve the operation of the vibrators 25.

In employing the above-described embodiments of the invention for cleaning the ball bearings 18, the liquid 13, preferably consisting of a solvent, is discharged by the elbow 11a causing the liquid 13 already-in the container 10 to spirally swirl toward the outlet 14. Preferably, the valve 16 is partially open .to permit the liquid 13 to carry dirt from the container 10 through the line 15. In order to conserve cleaning fluid, the line 15 may lead to a filter which permits the cleaning fluid to be reused by pumping to the line 12.

It has been found preferable in cleaning articles such as ball hearings to fill and maintain the depth of the liquid 13 in the container 10 at a quarter wavelength or odd multiple thereof of the sonic energy generated by the vibrators 25 to provide for standing compressional waves in the liquid 13 due to reflection from the surface thereof. However, it will be understood that this is notcritical-to the operation .of the invention. The rack 17 is formed with such-a diameter that it maybe positioned immediately over thevibrators 25. The ball bearings 18 to be cleaned are then placed on the fingers 17a.

After completion of the above-described preliminary steps providing for circulationof the liquid over the ball bearings 18 and down the outlet 14, the coils 29 are energized through the conductors 29a from a suitable A.-C. power supply (not shown), having an opti-- mum predetermined frequency for cleaning the ball bearings 18 in the container 10, this frequency having been determined by the choice of the one-half wavelength magnetostrictive stacks 26. For example, it has been found that frequencies from approximately 9 kilocycles to 30 kilocycles provide good cleaning efiicency, an optimum value being about 16 kilocycles.

Preferably, the coils 29 are connected to the power supply so that the magnetostrictive units 25 vibrate alternately, i. e., the alternating current is applied to alternate coils 29 out of phase. However, this is not essential and good results may be obtained without such phasing.

Upon energization of the coils 29, the well known phenomena of magnetostrictive vibration will occur in the stacks 26 and the sonic wave energy generated will be transferred through the members 28 and the bottom of the container 10 to the liquid 13 and the ball bearings 18. This elastic wave energy will cause each element of the .ball bearings 18 to expand and contract and greatly assist the cleaning fluid in removing the dirt, grease and other foreign substances found thereon. Furthermore, it has been found that the outer races 19 of the ball bearings will slowly rotate upon application of the sonic energy thereto so that all of the movable surfaces of the ball bearings 18 are exposed to the cleaning fluid providing, accordingly, exceptionally I thorough cleansing.

While several theories have been advanced to explain the rotation of the races 19, the most plausible appears to be that the sub-harmonic compressional waves generated in the liquid 13, due to the various combinations of standing waves provided by the reflection of sonic waves from the surface of the liquid 13, act to provide rotation of the races 19. It will be apparent that such movement is not limited to ball bearings alone, but will be useful in cleaning other similar articles having relatively movable surfaces.

The flow of the liquid 13 also assists rotation of the races 19. However, it has been found that the races rotate irrespective of such flow when adjacent vibrators are energized 180 out of phase.

The above-described apparatus has also been found useful, in pickling .metallic objects. Thus, such objects may be introduced into the container 10 on the rack 17, or merely placed on the bottom of the container 10, and acid introduced therein through the inlet 11. It will, of course, be understood that when the liquid introduced into the container 10 has a corrosive nature such as an acid, the container 10 may be formed from orlined with suitable materials such as glass or ceramics.

The subjection of the acid and objects to the high intensity sonic wave energy greatly accelerates the chemical reaction of the acid with the mill scale, rust or corrosion found on the objects and also drives off much of the nascent hydrogen generated by this reaction, resulting in a substantial reduction in embrittlement of the metallic surface due to such hydrogen. Further, it has been found that not only is the pickling process greatly accelerated but the surface of the metal from which oxides are re-' moved is polished, the pitting often found being greatly reduced by this process.

For example, a rusted steel object placed in a 50 percent solution of hydrochloric acid and water is cleaned almost instantaneously. However, the same object is relatively unaffected when immersed in a 10 percent solution of hydrochloric acid. However, two minutes .after sonic wave energy is applied to the 10 percent acid solution by theapparatus described above, the rust will be removed. Furthermore, asmentioned above, the nascent hydrogen formed by the reaction of the acid and the iron oxide tends to combine with the surface metal causing embrittlement thereof which is ordinarily removed by expensive heat treating processes. However, the application of sonic wave energy to the acid solution drives off much of the nascent hydrogen and greatly reduces such embrittlement. Preferably, the intensity of the applied sonic energy is great enough to produce cavitation in the liquid. Accordingly, it is evident that this process afiords substantial advantages by reducing the acid utilized and by eliminating expensive heat treatments for the metal objects pickled.

The advantages recited in connection with pickling are also gained when sonic wave energy is applied to an acid etching solution. It has been found that the unmasked portions of a metallic object to be etched are polished and lack brittleness due to the action of the sonic wave energy in accelerating the reaction of the acid solution with the metal and removing the nascent hydrogen from the solution.

Apparatus according to the present invention may also be employed to remove particles remaining on both metallie and non-metallic objects after a manufacturing operation such as machining which may leave burrs on the machined object. Thus, these objects may be placed in the liquid 13 in the container and the high intensity elastic vibrations will cause them to vibrate and separate the particles therefrom. It may be desirable to employ corrosive liquids such as acids in this instance and, accordingly, the container 10 may be made from or lined with suitable materials such as glass or ceramics, as mentioned above.

It will be understood that the above-described embodiments of the invention are illustrative only and modifications thereof will occur to those skilled in the art. For example, powdered compounds may be placed in the con tainer 10 for thorough compacting without the use of any liquid. Furthermore, a greater or lesser number of magnetostrictive transducers may be employed depending on the size of the container 10. and the processes to be performed. Therefore, the invention is not to be limited to the specific methods and apparatus disclosed herein but is to be defined by the appended claims.

I claim:

1. Apparatus for cleaning by sonic wave energy ball bearings formed by relatively movable inner and outer races and balls therebetween comprising a cylindrical container adapted to be filled with cleaning liquid, at least four magnetostrictive vibrators, sonic wave energy coupling means joining said vibrators to the bottom of said container in symmetrical relation thereto, electrical source means, means coupling said vibrators to said source means for energizing adjacent vibrators out of phase when an even number of said vibrators are used and for energizing adjacent vibrators with the exception of two adja cent vibrators 180 out of phase when an odd number of said vibrators are used, a rack formed to support each of: said bearings by, the inner race in the liquid so that upon energization of said vibrators and generation of the sonic wave energy, said outer race will rotate about said inner race.

2. Apparatus for cleaning by sonic wave energy ball bearings formed by relatively movable inner and outer races and balls therebetween comprising a cylindrical container, an inlet disposed on the side of said container adapted to be connected to a source of cleaning liquid for at least partially filling said container, said inlet being directed circumferentially to said container, an outlet centrally disposed in the bottom of said container, a plurality of magnetostrictive vibrators adapted to be energized by an electrical source, sonic wave energy coupling means joining said vibrators to the bottom of said container in symmetrical relation thereto, a rack formed to support each of said bearings by the inner race in the liquid so that upon energization of said vibrators and generation of said sonic wave energy, said outer race will rotate about said inner race.

3. Apparatus as defined in claim 2 wherein said rack is positioned directly over said coupling means.

4. Apparatus as defined in claim 2 wherein each of said sonic wave energy coupling means consists of a truncated conical member provided with a hollowed out portion at the larger end thereof, said portion communicating with the bottom of said container.

5. Apparatus as defined in claim 2 wherein the depth of said cleaning liquid is maintained at an odd multiple of a quarter wavelength of said sonic wave energy.

References Cited in the file of this patent UNITED STATES PATENTS 972,736 Tippit Oct. 11, 1910 1,665,423 Skelton Apr. 10, 1928 2,259,260 Matteson Oct. 14, 1941 2,369,498 Streuber Feb. 13, 1945 2,496,506 Wagner Feb. 7, 1950 2,498,990 Fryklund Feb. 28, 1950 2,527,666 Winter Oct. 31, 1950 2,554,701 Hackett May 29, 1951 2,604,895 Fechter July 29, 1952 2,612,860 Pendleton Oct. 7, 1952 2,616,820 Bourgeaux Nov. 4, 1952 

